The present invention relates generally to semiconductor device processing techniques and, more particularly, to a structure and method for stochastic integrated circuit personalization.
Authentication is a very effective means to prevent faking or counterfeiting in the world or commercial transactions. Different means of authentication have been implemented in various industries such as, for example: the use of laser holograms in credit cards, unique water marks or embedded metal threads in monetary bills, and certain types of embedded smart chips in passports or driver's licenses. An underlying mechanism of each of these schemes is the incorporation of unique identification keys for each device or product, the keys being unique in that they are very difficult to reproduce from a statistical standpoint. In principle, the longer the identification key, the more difficult it becomes to crack the key.
In the case of a semiconductor device, physical features are typically formed through the use of photolithographic patterning and etching of layers, using one or more designed masks with the desired features to be defined in the device layers. However, in order to form a physically unique structure from chip to chip, a specifically designed mask is ordinarily required. In terms of providing a sufficiently secure identification key using unique patterns on a device, the sheer number of individual masks needed to provide a significant number of customized features becomes too impractical a task.
Accordingly, it would be desirable to be able to form a customized integrated circuit device having randomly distributed features or characteristics such that it is possible to create a secure identification key for an individual chip, and in a manner that is practical and relatively easy to incorporate within existing semiconductor fabrication capabilities.